Mailbox names are 7-bit. Client implementations MUST NOT attempt to
create 8-bit mailbox names, and SHOULD interpret any 8-bit mailbox
names returned by LIST or LSUB as UTF-8. Server implementations
SHOULD prohibit the creation of 8-bit mailbox names, and SHOULD NOT
return 8-bit mailbox names in LIST or LSUB.
The reason is given:
Note: 8-bit mailbox names were undefined in earlier
versions of this protocol. Some sites used a local 8-bit
character set to represent non-ASCII mailbox names. Such
usage is not interoperable, and is now formally deprecated.The desired end state is to allow UTF-8 mailbox names, but we can't do that until we first exterminate ISO-8859-1, EUC, and especially(!!) Shift-JIS mailbox names. The extermination is well under way (and has been for years); but unfortunately is not yet complete.
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
